1: Measuring Matter and Energy

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The study of chemistry will open your eyes to a fascinating world. Chemical processes are continuously at work all around us. They happen as you cook and eat food, strike a match, shampoo your hair, and even read this page. Chemistry is called the central science because a knowledge of chemical principles is essential for other sciences. You might be surprised at the extent to which chemistry pervades your life.

• 1.1: What is Chemistry
Chemistry is the study of matter and how it behaves. The scientific method is the general process by which we learn about the natural universe.
• 1.2: Classification of Matter
Matter can be described with both physical properties and chemical properties. Matter can be identified as an element, a compound, or a mixture.
• 1.3: Introduction to Kinetic and Potential Energy
Chemists often separate energy into two categories. Kinetic energy is energy possessed by a moving object, while potential energy is energy due to position, often relative to some other object or field. When you stand at the top of a stairwell you have more potential energy than when you are at the bottom, because the earth can pull you down through the force of gravity, doing work in the process.
• 1.4: Measurements
Chemists measure the properties of matter and express these measurements as quantities. A quantity is an amount of something and consists of a number and a unit. The number tells us how many (or how much), and the unit tells us what the scale of measurement is. For example, when a distance is reported as “5 kilometers,” we know that the quantity has been expressed in units of kilometers and that the number of kilometers is 5.
• 1.5: Expressing Numbers: Scientific Notation
Large or small numbers are expressed in scientific notation, which use powers of 10.
• 1.6: Expressing Numbers: Significant Figures
Significant figures properly report the number of measured and estimated digits in a measurement. There are rules for applying significant figures in calculations.
• 1.7: The International System of Units
Recognize the SI base units. Combining prefixes with base units creates new units of larger or smaller sizes.
• 1.8: Converting Units
A unit can be converted to another unit of the same type with a conversion factor.
• 1.9: Temperature Conversions
The concept of temperature may seem familiar to you, but many people confuse temperature with heat. Temperature is a measure of how hot or cold an object is relative to another object (its thermal energy content), whereas heat is the flow of thermal energy between objects with different temperatures. Three different scales are commonly used to measure temperature: Fahrenheit (expressed as °F), Celsius (°C), and Kelvin (K).
• 1.10: Specific Heat
Heat transfer is related to temperature change. Heat is equal to the product of the mass, the change in temperature, and a proportionality constant called the specific heat.
• 1.11: Dosage Calculations
The dosage, route, concentration, and division over time may all be critical considerations in the administering of drugs, or in responding to exposure to a toxin.
• 1.12: Chapter Summary
To ensure that you understand the material in this chapter, you should review the meanings of the bold terms in the following summary and ask yourself how they relate to the topics in the chapter.

1: Measuring Matter and Energy is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by LibreTexts.